Attack on Titan 2

To get an S rank in a mission, you need to earn an S in all 3 subcategories.
You will need to kill a large amount of Titans, complete all side-missions and finish the level under par time.
The best mission to do this achievement is on the tutorial, as there are no side missions to worry about. Complete the ODM section as quickly as possible to move onto the combat tutorial. Follow the instructions to progress to the wooded area.
Once the timer starts, eliminate all the dummy titans as quickly as possible before the timer runs out.
This can be earned at the same time as the “Top Level Cadet” achievement for killing the most dummy titans in this section.

The way to get an S rank if by doing the following:
-Kill as many titans as possible
-Complete all side missions
-Finish the map as soon as you can

At the end of each mission you will see your score. If you got an A or below, see which sections needs improvement and go back and redo it =)